Photochromoscope or photochromoscope-camera.



(Application med Huy 1, 1899.)

9 9 8 7, n. A. nu B E w m .I M C ...u E P P 0 C S 0 n 0 B .H C wm W0...n EP .D FN IL A E P 0 C Y* S 0 M U R H C 0 T 0 3 ...n 5 P M 2 w 5 3 60. Y N n w (lo lodel.)

.les

peana-Inn UNITED STATES yPATENT OFFICE.

FREDERIC EUGENE IVES, OF PHILADELPHIA, PENXSYI'ANIA.

PHOTOCHROMOSCOPE OR PHOTOCHROMOSCOPE-CAMERA.A

SPECIFICATION forming part of Letters Patent No. 635,253, dated October17, 1899.

Application filed May l., 1899.

To all 107mm it may concern:

13e it known that I, FREDERIC EUGEXE IvEs, a citizen of the UnitedStates, residing in Philadelphia, Pennsylvania, have invented certainImprovements in Photoehromoscopes or Photochromoscope-Cameras, of whichthe following is a specification.

My invention consists of a certain improvement in photochromoscopes orphotoehromoscope-cameras, more especially in that for which I obtainedLetters Patentof the United States No. 501,040, dated December 18, 1801,the object of my present invention being to introduce in a reflectedimage or images a distortion corresponding to that produced in atransmitted image or images by reason of the inclination of thetransparent mirror or mirrors interposed in the path of the rays oflight from such image or images and to accomplish this without specialtreatment or formation of the transparent mirrors.

tain in the manner hereinafter set forth, referenee heilig had to theaccom panying drawings, in which- Figure 1 represents in verticalsection a photochromoscope instrument in which my present invention isembodied; and Fig. 3 is a similar view of another form ofphotochromoscope instrument, illustrating another embodiment of myinvention.

In the instrument shown in Fig. 1, J represents a easin g, which ispreferably hinged at the front lower corner to the front of a box J orother base, on which, by means of a suitable strut and set-screw, thecasing may be adjusted at the best angle for properly transmitting thelight.

IVhen the instrument is used for viewing a chr'iogram, the tlireesections of tlie chromogram A', B', and D are disposed, respectively, infront of and above openings in the casing of the instrument, as shown inthe drawings, the light passing directly through the sections B and D ofthe chromogram and being reflected through the section A' by means of anexternal mirror A2. lVithin the casing of the instrument are thecolor-screens A3, B3, and D3 and the inclined transparent mirrors B2 andD2, the mirror Bi reflecting the rays of light which pass through theimage or section of the chromogram B' and transmitting the rays whichare reflected by the mirror A2 through the image or section of thechromogram A', while the mirror D2 reflects the rays This object I at-Serial No. 715,229. (No model.)

i the ehromogram D' and transmit-the rays rej ected from the mirrors A2and 132. When l the instrument is used as a camera, the light i ofcourse travels in the opposite direction and g forms images at A', ll',and D', respectively, sensitive plates of course taking the place of lthe ehromograms.

e In the original instrument of this character f the inclination of thetransparent reflectors f necessary to secure an optical superposition ofthe di fferentimagcs to the eye caused a distortion of the image seen bythe transmit-ted rays, owing tothe different angles at which differentportions of the cone ot' light entered the surface of thetransmitting-mirrors and to the consequent differences of refraction,the efj feet, if the mirrors had plane parallelsurfaees, being that theimage transmitted through Dz l from B2 and that transmitted through bothB'iandDfappeared pcrpendieularlyelongated to a slight extent sufiicientto prevent all of the details of the picture from registering accuratelywith the salnedetails in the image which was simply reflected from D2.In the i camera a reverse effect resulted-that is g to say, the imagesformed by reflection and l transmission appeared perpendicularlyshortened as compared with that which was simply reflected. This defectcan be corrected by employing transparent mirrors which instead ofhaving plane surfaces exactly parallel to each other are slightlyEgg-shaped and so disposed that the lowest part of the picture seenthrough the mirror appears optically displaced upward, while thedisplacement appears less and less toward the top, where theinclina-tion of the transparent mirror brings it closer and closer tothe photographic image or where in a camera the reverse effect results.The preparation of suitably-wedged mirrors with certainty is, however,difficult and costly, and in Letters Patent- No. 622,480, granted to meon the 1th day of April, 1899, I described and claimed a method ofdistorting the figure of the retiecting-snrface of the transparentmirror by the application of local pressure thereto by means of springsor other pressure devices.

My present invention comprises another method of overcoming the defectto which I have referred, and in that form of instrument shown in Fig. 1it consists simply in locating between the primary mirror Dzof theinstrument and the image D' through which the rays pass to said mirror aplate or sheet of glass inclined in such a manner as to cause distortionof the image D' equivalent to the distortion of the image A' after ithas passed through the mirror D2. It may be said that this provision forcounterbalancing the distortion of the image A' by the inclinedtransmitting-mirrors would more than counterbalance the distortion ofthe image B', owing to the fact that this latter image is transmittedthrough but one inclined mirror; but this is unimportant if the image B/is that of the blue sensation, for it has been found in practice thatthis image has less noticeable edects of definition in the compositeimage than the images of the red and green sensations. Hence the slightovercorrection of the red image as compared with the blue image iscomparatively unimportant. Nevertheless, in certain forms ofphotochromoscope or photochromoscope-camera a properly formed andinclined glass may be inserted under the image B', or instead of using aspecial inclined transparent plate I may make and incline the colorscreen or screens so as to obtain the same result. These embodiments ofthe invention are illustrated in Fig. 2, in which B3 and D3 representcolor-screens thus disposed in respect to the inclined transparentmirrors B2 and D2. In this case also the mirrors A2, B2, and D2 aredisposed one behind another in the same axial line, and the box orcasing has three steps, a chromogram or plate being disposed upon thetop of each step. Assuming,r that the transparent reflectors have planeparallel surfaces, the compensating glass or glasses, if inclined at thesame angle as the transparent reflectors, should be of a thicknesssubstantially equal to that of the single mirror or to that of bothmirrors whose distortion said compensating-glass is intended to correct,a greater thickness being necessary if the inclination is less and aless thickness if the inclination is greater.

It is evident that I may employ this device conjointly with that claimedin Patent No.

22,480, if desired.

Either of the instruments described may be used as a camera, thedirection of the rays of light in such case being the reverse of that inthe photochromoscope and sensitive plates taking the place of thechromograms.

Having thus described my invention, I claim and desire to secure byLetters Patent- 1. An instrument of the character t' escribed, having aseries of inclined transparent mirrors and an inclined transparentdistortioncorrecting plate located in the path of the rays which aresubject to reflection by the primary transparent mirror,the thickness ofsaid correcting-plate being substantially equal to the combinedthickness of the mirrors whose distortion it is to correct if its angleto the optical axis is the same, and greater or less than the combinedthickness of said mirrors according as its angle to the optical axis isless or greater than that of said mirrors, whereby distortion of theimage reflected by said primary mirror will be elected substantiallyproportionate to the distortion of the images transmitted therethrough.

2. An instrument of the character described having a series of inclinedtransparent mirrors and inclined transparent distortion-correctingplatesI located in the paths of the rays which are subject to reflectionby first and second transparent mirrors of the series, the thickness ofeach correcting-plate being substantially equal to the thickness of themirror or mirrors whose distortion it is to correct, if its angle to thcoptical axis is the same, and greater or less than the thickness of saidmirror or mirrors, according as its angle to the optical axis is less orgreater than that of said mirror or mirrors, whereby distortion of theimage reected by each transparent mirror will be eected substantiallyproportionate to the distortion ot' the image or images transmittedtherethrough.

3. An instrument of the character described having a series of inclinedtransparent mirrors and an inclined transparent distortioncorrectingplate colored so as to serve as a color-screen, said plate being locatedin the path of the rays which are subject to redection by the primarytransparent mirror and having a thickness substantially equal to thecombined thickness of the mirrors whose distortion it is to correct ifits angle to the optical axis is the same, and greater or less than thecombined thickness of said mirrors according as its angle to the opticalaxis is less or greater than that of said mirrors, whereby distortion ofthe ilnage reflected by said primarymirror will be effectedsubstantially proportionate to the distortion of the images transmittedtherethrough.

4. An instrument of the character described having a series of inclinedtransparent mirrors and inclined transparent distortion-correctingplates colored so as to serve also as color-screens, said plates beinglocated in the paths of the rays which are subject to reflection by thefirst and second transparent mirrors of the series au d each having athickness substantially equa-l to the thickness of the mirror or mirrorswhose distortion it is to correct, if its angle to the optical axis isthe same, and greater or less than the thickness of said mirror ormirrors according as its angle to the optical axis is less or greaterthan that of said mirror or mirrors, whereby distortion of the imagereflected by each transparent mirror will be effected substantiallyproportionate to the distortion of the image or images transmittedtherethrough.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing witnesses.

FREDERIC EUGENE IVES.

Witnesses F. E. BEcHToLD, J os. H. KLEIN.

i s e IIO

